Is there an "oficial" palette for this? 

Hi Siridakis,

There isnt an official palette per say (even the colours between gameboys themselves were never 100 percent the same) but anything that looks gameboy like is fine.
Feel free to change it up too! The palette I use tends to have a little more blue in there to make it pop.

Thanks :) 

Here are some suggestions: https://lospec.com/palette-list/tag/gameboy

Important Jam update here: https://itch.io/jam/gbjam2018/topic/272198/this-gameboy-jam-is-cancelled